OOOOhhhhh you make it sound soooo easy. Your better off putting a 16v head on as it is far less hassle. Even that is no walk in the park. Are you planning on using std engine management??? You will need to change taht as your std computer is not going to run a 4a head and fuel system. You could do the dodgy and integrate your 7a injectors and distributor and stuff but as Tom'sGPturbo found out on his GPcorolla turbo conversion this is not a good option.
Do a search on toymods as there was some info on there ages ago. I also spoke to a guy who rallied a 7afe powered corolla on there too about how strong the bottom ends are. PLenty of $$$ there for shotpeening, de-burring, and balancing etc of the rods. The 7age will not revv as high as the 4age either.
As for turboing, I hope you have plenty of spare cash. Things you need to consider are fuel pump, injectors, intercooler, engine management manifold and turbo and a good tuner otherwise you will be spending a lot of money on an engine that will be an unreliable hand grenade.
This is going to sound really boring and make me sound like the old fart taht I am but enjoy the car for what it is, a cheap and economical daily driver and spend your money on a fun car that you can afford to have off the road for weeks at a time. Otherwise get used to public transport.